1. Field of the Invention
A preferred embodiment of the present invention relates to distributed databases. In particular, a preferred embodiment of the present invention relates to a system and method for determination of replication horizons and other related data propagation methods within such as system.
2. Description of the Background Art
Distributed computing networks are becoming more and more popular. With increased business use of the Internet, the need for more efficient, distributed computing system has become critical. The business use of the Internet has forced the integration of disparate computing environments with distributed computing systems that enable data transfer between such disparate systems. However, this in turn has created a need for ways to ensure that the data stored on various distributed systems are coherent and do not contain inconsistent information.
Conventional independent distributed database (IDDB) systems provide for multiple, simultaneous, potentially geographically dispersed, replicated copies of a database. This architecture allows continuous, high quality-of-service, local data access to multiple users regardless of their respective locations and regardless of the quality or availability of network connectivity between the database sites. The IDDB also provides for update-anywhere capabilities. That is, all sites running the system can perform local, autonomous database updates and the IDDB guarantees that these updates flow to all sites within the IDDB network. Each site's updates are treated equally and a site's update is only overridden in the case of a direct data conflict when, for the most part, the latest chronological change will survive. The replication process occurs asynchronously to, and is not triggered by, the data updates.
Common questions asked by users of an IDDB database are “How do I know when my changes are visible to a specific site?” and “How do I know when my changes are visible to the whole network?” While an IDDB system provides many benefits in terms of data availability and quality of service, it does not insure that all sites within an IDDB network simultaneously, and in real-time, contain exact replicas of one another's data. Rather, the IDDB system guarantees that, over time, data changes created at any site within the IDDB network will propagate to all other sites in the IDDB network. For many mission critical, data-centric applications, the benefit of continuous, high performance, local data access far outweighs the need for the instantaneous data replication that can only be provided by a centralized database model. That being said, it is often of interest to be able to determine the point in time where a particular data change, at a particular IDDB site, is known to have successfully propagated to all other sites in the IDDB network.